1. Field
The present disclosure relates to semi-permeable membranes, production methods thereof, and water treatment devices including the same.
2. Description of the Related Art
Osmosis (or forward osmosis) refers to a phenomenon wherein water moves from a lower solute concentration solution to a solution of a higher solute concentration by osmotic pressure. Reverse osmosis is a method of artificially applying pressure to move water in the opposite direction. The forward and the reverse osmosis methods are commonly used in a water treatment application such as water purification and desalination.
In the reverse osmosis water treatment, a pressure corresponding to the osmotic pressure generated by dissolved substances is applied to separate the dissolved substances from water. To this end, developing a semi-permeable membrane (e.g., a thin film membrane or a thin film composite membrane) having higher water flux and improved performance for excluding salts is desired.
The water reverse osmosis treatment involves artificially applying a relatively high pressure and thus entails relatively high energy consumption. To increase energy efficiency, a forward osmosis process using the principle of osmotic pressure has been suggested. The forward osmosis process uses osmotic pressure that is generated by the difference between the feed solution and a draw solution. Therefore, in order for the forward osmosis process to be used effectively, it is important to develop a semi-permeable membrane that may provide a relatively high osmotic pressure between the feed solution and the draw solution and minimize reverse salt flux of draw solutes while facilitating the flow of water from the feed solution to the draw solution.